The brown recluse spider or violin spider, Loxosceles reclusa, is a well-known member of the family Sicariidae (formerly placed in a family "Loxoscelidae").Brown recluse spiders are usually between 6–20 mm (¼ in and ¾ in), but may grow larger. They may be brown or gray and usually have markings on the dorsal side of their cephalothorax, with a black line coming from it that looks like a violin with the neck of the violin pointing to the rear of the spider, resulting in the nicknames fiddleback spider, brown fiddler or violin spider.
A brown recluse's stance on a flat surface is usually with all legs well extended unless alarmed, when it may withdraw its forward two legs straight rearward into a defensive position, withdraw its rear pair of legs into a position for lunging forward, and raise the pedipalps.
Movement at virtually any speed is an evenly paced gait with legs extended, stopping naturally when renewing its internal hydraulic blood pressure (that, like most spiders, it requires to renew strength in the legs); it then continues at a steady pace until again it needs to renew its blood pressure.
When threatened it usually flees, seemingly to avoid a conflict, and if detained may further avoid contact with fast horizontal rotating movements.
As indicated by its name, this species is rarely aggressive, and actual brown recluse bites are rare. The spider usually bites only when pressed against the skin, such as when tangled up within clothes, bath towels, or in bedding. Many human victims of brown recluse bites report having been bitten after putting on clothes that had not recently been worn or disturbed. In fact, many wounds that are necrotic and diagnosed as brown recluse bites can actually be methicillin-resistant Staphylococcus aureus (MRSA) or simple staphylococcus infections. Other causes include skin cancer, Lyme disease, and other infected insect bites and skin lesions. Brown recluse bites may produce a range of symptoms known as loxoscelism. There are two types of loxoscelism: cutaneous (skin) and systemic (viscerocutaneous).
Bite treatment
First aid involves the application of an ice pack to control inflammation, the application of aloe vera to soothe and help control the pain, and prompt medical care. If it can be easily captured, the spider should be brought with the patient in a clear, tightly closed container so it may be identified.
There is no established treatment for necrosis. Routine treatment should include elevation and immobilization of the affected limb, application of ice, local wound care, and tetanus prophylaxis. Many other therapies have been used with varying degrees of success including hyperbaric oxygen, dapsone, antihistamines (e.g., cyproheptadine), antibiotics, dextran, glucocorticoids, vasodilators, heparin, nitroglycerin, electric shock, curettage, surgical excision, and antivenom. None of these treatments have been subjected to randomized controlled trials to conclusively show benefit. In almost all cases, bites are self-limited and typically heal without any medical intervention.
It is important to seek medical treatment if a brown recluse bite is suspected, as in the rare cases of necrosis the effects can quickly spread, particularly when the venom reaches a blood vessel. Cases of brown recluse venom traveling along a limb through a vein or artery are rare, but the resulting mortification of the tissue can affect an area as large as several inches, to the extreme of requiring excising of the wound.
refference:
wikipedia.org
There is no established treatment for necrosis. Routine treatment should include elevation and immobilization of the affected limb, application of ice, local wound care, and tetanus prophylaxis. Many other therapies have been used with varying degrees of success including hyperbaric oxygen, dapsone, antihistamines (e.g., cyproheptadine), antibiotics, dextran, glucocorticoids, vasodilators, heparin, nitroglycerin, electric shock, curettage, surgical excision, and antivenom. None of these treatments have been subjected to randomized controlled trials to conclusively show benefit. In almost all cases, bites are self-limited and typically heal without any medical intervention.
It is important to seek medical treatment if a brown recluse bite is suspected, as in the rare cases of necrosis the effects can quickly spread, particularly when the venom reaches a blood vessel. Cases of brown recluse venom traveling along a limb through a vein or artery are rare, but the resulting mortification of the tissue can affect an area as large as several inches, to the extreme of requiring excising of the wound.
refference:
wikipedia.org
